Immunohistochemical analysis of steroid hormone receptors in nasopharyngeal angiofibromas

Integrated Molecular and Histological Insights for Targeted Therapies in Mesenchymal Sinonasal Tract Tumors

PURPOSE OF REVIEW

This review aims to provide a comprehensive overview of mesenchymal sinonasal tract tumors (STTs), a distinct subset of STTs. Despite their rarity, mesenchymal STTs represent a unique clinical challenge, characterized by their rarity, often slow progression, and frequently subtle or overlooked symptoms. The complex anatomy of the sinonasal area, which includes critical structures such as the orbit, brain, and cranial nerves, further complicates surgical treatment options. This underscores an urgent need for more advanced and specialized therapeutic approaches.

RECENT FINDINGS

Advancements in molecular diagnostics, particularly in next-generation sequencing, have significantly enhanced our understanding of STTs. Consequently, the World Health Organization has updated its tumor classification to better reflect the distinct histological and molecular profiles of these tumors, as well as to categorize mesenchymal STTs with greater accuracy. The growing understanding of the molecular characteristics of mesenchymal STTs opens new possibilities for targeted therapeutic interventions, marking a significant shift in treatment paradigms. This review article concentrates on mesenchymal STTs, specifically addressing sinonasal tract angiofibroma, sinonasal glomangiopericytoma, biphenotypic sinonasal sarcoma, and skull base chordoma. These entities are marked by unique histopathological and molecular features, which challenge conventional treatment approaches and simultaneously open avenues for novel targeted therapies. Our discussion is geared towards delineating the molecular underpinnings of mesenchymal STTs, with the objective of enhancing therapeutic strategies and addressing the existing shortcomings in the management of these intricate tumors.

The Genetic and Molecular Determinants of Juvenile Nasopharyngeal Angiofibroma: A Systematic Review

Objective:

Juvenile nasopharyngeal angiofibroma (JNA) is a rare vascular tumor of unknown etiology. Studies investigating the molecular and genetic determinants of JNA are limited by small sample size and inconsistent approaches. The purpose of this study is to examine all eligible JNA studies in aggregate, applying qualitative analysis to highlight areas of particular relevance, including potential targets for therapeutic intervention.

Methods:

The PubMed, MEDLINE, Embase, Web of Science, Cochrane, and CINAHL databases were screened with inclusion and exclusion criteria applied to all citations. Manuscripts investigating the genetic determinants, histopathogenesis, and heritability of juvenile nasopharyngeal angiofibroma were included. Non-English studies, case reports, and articles focusing on clinical management without original data were excluded. Full text articles were obtained. A qualitative synthesis of data was performed.

Results:

A total of 59 articles met criteria for inclusion. These were divided into 6 categories based on the primary topic or target discussed, (1) steroid hormone receptors, (2) chromosomal abnormalities, (3) growth factors, (4) genetic targets, (5) molecular targets, (6) Wnt cell signaling, and (7) studies that overlapped multiple of the aforementioned categories. Although relatively low n values prevent definitive conclusions to be drawn, a predominance of certain molecular targets such as vascular endothelial growth factor (VEGF) and Wnt/β-catenin pathway intermediaries is apparent.

Conclusions:

Although the etiology of JNA remains elusive, contemporary molecular genetic investigation holds promise for risk stratification and could form the basis of a modernized staging system. A multicenter clinical registry and linked tissue bank would further promote the search for JNA specific biomarkers.

Variable expression of molecular markers in juvenile nasopharyngeal angiofibroma

Background:

Molecular categorisation may explain the wide variation in the clinical characteristics of juvenile nasopharyngeal angiofibroma.

Methods:

Variations in molecular markers in juvenile nasopharyngeal angiofibroma in an Indian population were investigated and compared with global reports.

Results:

Variable molecular marker expression was demonstrated at the regional and global levels. A wide variation in molecular characteristics is evident. Molecular data have been reported for only 11 countries, indicating a clear geographical bias. Only 58 markers have been studied, and most are yet to be validated.

Conclusion:

Research into the molecular epidemiology of juvenile nasopharyngeal angiofibroma is still in its infancy. Although the molecular variation is not well understood, data obtained so far have prompted important research questions. Hence, multicentre collaborative molecular studies are needed to establish the aetiopathogenesis and establish molecular surrogates for clinical characteristics.

Nasal juvenile angiofibroma: Current perspectives with emphasis on management

Juvenile angiofibroma is an uncommon, benign, locally aggressive vascular tumor. It is found almost exclusively in young men. Common presenting symptoms include nasal obstruction and epistaxis. More advanced tumors may present with facial swelling and visual or neurological disturbances. The evaluation of patients with juvenile angiofibroma relies on diagnostic imaging. Preoperative biopsy is not recommended. The mainstay of treatment is resection combined with preoperative embolization. Endoscopic surgery is the approach of choice in early stages, whereas, in advanced stages, open or endoscopic approaches are feasible in expert hands. Postoperative radiotherapy (RT) or stereotactic radiosurgery seem valuable in long-term control of juvenile angiofibroma, particularly those that extend to anatomically critical areas unsuitable for complete resection. Chemotherapy and hormone therapy are ineffective. The purpose of the present review was to update current aspects of knowledge related to this rare and challenging disease. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1033-1045, 2017.

Human Papilloma virus in Juvenile Nasopharyngeal Angiofibroma: possible recent trend

BACKGROUND

Juvenile nasopharyngeal angiofibroma (JNA) has witnessed a four-fold increase in the incidence at our facility in the current decade as compared to the 1980s. With high global incidence of human pappilloma virus (HPV) related oropharyngeal cancer in India, we hypothesize its implication in JNA as it has not yet been reported.

METHODS

Clinico-Surgical variables of 6 patients of JNA were included for correlation and their tissue samples were subjected to western blotting (WB), polymerase chain reaction and immunoflorescence to demonstrate a definite association with HPV. In addition 6 control samples (adenoids) underwent WB analysis.

OBSERVATIONS

A universal presence of HPV with JNA is novel 'discovery' and has suggested a possibility of a definite association. Only a single case suggested weak infection. None of the controls suggested infection, thus ruling out the presence of HPV in nasopharynx of normal population.

INTERPRETATION

With the dawn of this definite association, no specific conclusions can yet be drawn but a whole plethora of questions have emerged with our novel 'discovery'.

Toll-like receptors 3, 7, and 9 in Juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibroma (JNA) is a rare, benign tumor affecting adolescent males. The etiology of JNA as well as the causes determining the variable growth patterns of individual tumors remains unknown. Toll-like receptors (TLRs) are part of the innate immune response to microbes; by recognition of distinct features, they link to induction of pro-inflammatory signaling pathways. We immunostained TLR 3, 7, and 9 in 27 JNA specimens of patients treated at the Helsinki University Central Hospital, Helsinki, Finland, during the years 1970-2009.

RESULTS

TLR 3, 7, and 9 expressions were found in stromal and endothelial cells of JNA, and their expression levels varied from negative to very strong positive. TLR 3 expression was found to have a significant correlation with the clinical stage of JNA.

CONCLUSIONS

The present results propose a putative role of TLRs in the growth process of JNA.

Expression of sex hormone receptors in juvenile angiofibromas and antiproliferative effects of receptor modulators

BACKGROUND

Predilection of juvenile angiofibromas in adolescent boys has prompted the hypothesis of hormone-dependent tumor growth. However, knowledge on expression and function of sex hormone receptors in juvenile angiofibromas is still sparse and inconsistent.

METHODS

Transcript and protein expression of sex hormone receptors in juvenile angiofibromas was studied by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and immunohistology/fluorescence. A bromodeoxyuridine assay was used to assess the antiproliferative effects of flutamide (androgen receptor antagonist) and tamoxifen (estrogen receptor modulator).

RESULTS

Significantly increased transcript levels were observed for androgen receptor, estrogen receptor α, follicle-stimulating hormone receptor, and luteinizing hormone receptor in juvenile angiofibromas versus the stroma of nasal mucosa. Estrogen receptor β and progesterone receptor mRNA levels were low and similar for both tissues. Estrogen receptor α protein was detected in juvenile angiofibroma tumors and mesenchymal cell lines. Flutamide and tamoxifen inhibited proliferation of cultured juvenile angiofibroma mesenchymal cells.

CONCLUSION

These findings contribute to the understanding of juvenile angiofibroma pathophysiology and offer novel therapeutic options.

Fibroblastic and myofibroblastic tumors in children and adolescents

Fibroblastic and myofibroblastic tumors in children and adolescents are a relatively common group of soft tissue proliferations that range from reactive to hamartomatous to neoplastic, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic and immunohistochemical overlap, despite significant clinical, genetic, and prognostic differences. The fibromatoses are a major subgroup, and all types of fibromatoses can occur in the 1st 2 decades of life. Intermediate and malignant fibroblastic-myofibroblastic tumors are an important group that includes variants of fibrosarcoma and other tumors with recurrent cytogenetic or molecular genetic abnormalities and low metastatic potential. Pathologic examination is enhanced by adjunct techniques, such as immunohistochemistry, cytogenetics, and molecular genetics, although morphology provides the ultimate criteria for a specific diagnosis. This article reviews the clinicopathologic features of fibroblastic and myofibroblastic tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents, the use of diagnostic adjuncts, and differential diagnoses.

Anti-proliferative effect of glucocorticoids on mesenchymal cells in juvenile angiofibromas

BACKGROUND

Glucocorticoids (GCs) not only regulate metabolic and inflammatory mechanisms, but also are known to suppress tumor growth. Despite previous detection of glucocorticoid receptors (GRs) in juvenile angiofibromas, their distribution and function have not further been studied.

METHODS

Juvenile angiofibroma tissue (n = 30), nasal mucosa specimens (n = 10), subepithelial stroma of nasal mucosa (n = 20), and primary fibroblasts from juvenile angiofibroma (n = 6) and nasal mucosa samples (n = 6) were analyzed by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence staining. The antiproliferative effect of GCs (dexamethasone, prednisolone, and hydrocortisone) in vitro was assessed using a bromdeoxyuridine (BrdU) assay.

RESULTS

An upregulation of GR transcripts and protein was shown in juvenile angiofibroma tissue and primary mesenchymal cells compared to nasal mucosa. Application of GCs resulted in a significantly higher antiproliferative effect on juvenile angiofibroma versus nasal mucosa fibroblasts in vitro.

CONCLUSION

Expression of GRs and antiproliferative effects of GCs on juvenile angiofibroma fibroblasts offer novel options for the treatment of this unique fibrovascular tumor.

Juvenile nasopharyngeal angiofibroma with intracranial extension

OBJECTIVE

To provide a critical evaluation of the historical evolution of the surgical treatment of juvenile nasopharyngeal angiofibroma (JNA) with intracranial extension.

STUDY DESIGN

Case series with chart review.

SETTING

Skull base multidisciplinary group at the Instituto de Neurologia de Curitiba, Brazil.

SUBJECTS AND METHODS

From 1988 to 2000, the multidisciplinary skull base group surgically treated 67 adolescent boys with JNA, 20 of whom presented with intracranial extension. All patients presented involvement of the cavernous sinus, and 5 of them spread into the orbit. Before 2008, the authors combined microscopic-endoscopic techniques. After this period, the surgical approach used was facial degloving, associated with purely endoscopic technique patients.

RESULTS

Total tumor removal was achieved in 17 cases in the first surgery. In this series, the intracranial extension was extradural in all cases. There was only 1 case of cerebrospinal fluid leakage, which was promptly identified and treated. There was no mortality or permanent morbidity.

CONCLUSION

Radical removal of large JNA may be difficult because of its extreme vascularity and extension to the cavernous sinus, orbit, middle and anterior fossa. Nevertheless, most of JNA with intracranial extension can be resected in the first operation with minimal morbidity through a facial degloving and further combination of expanded endoscopic endonasal approaches.

The changing surgical management of juvenile nasopharyngeal angiofibroma

The management of juvenile nasopharyngeal angiofibroma (JNA) has changed during the last decades but it still continues to be a challenge for the multidisciplinary head and neck surgical team. The aim of this study was to review the used treatment approach and outcome of JNA in a single institution series of 27 patients diagnosed and treated during the years 1970-2009. All patients were male, with the median age of 17 years (range 11-33 years). Surgery was used as the primary treatment in every case. Surgical approaches varied, transpalatal approach (N = 14) being the most common approach used in this series. During the last decade various other techniques were applied, including endoscopic (N = 3) resection. Two patients were additionally treated with antiangiogenic agents and one patient with stereotactic radiotherapy. The primary recurrence rate was 37% and it seemed to correlate with vascular density of tumour and the surgical approach used. We suggest that the management of JNA should be planned by an experienced head and neck surgeon, as part of a multidisciplinary team, preferably in a tertiary referral setting, and the recent development of the available therapies should be taken into account to minimise the risk of recurrence.

[Orbital tumors arising from paranasal sinuses]

Orbital tumors arising from paranasal sinuses comprise mucoceles and malignant ethmoidal tumors. Most often, anamnestic, clinical, and radiological data as well as endoscopic biopsy performed by an ENT surgeon provide the preoperative diagnosis. If the tumor is benign, surgery can cure the patient. It is associated with chemotherapy and radiotherapy if the tumor is malignant.

Epstein-Barr virus and human herpes virus-8 are not associated with juvenile nasopharyngeal angiofibroma

BACKGROUND

Nasopharyngeal angiofibroma (also known as juvenile nasopharyngeal angiofibroma) is a rare fibroblastic tumor with a vascular component that occurs in the nasopharynx and posterolateral nasal wall of adolescent boys. The etiology of nasopharyngeal angiofibroma remains elusive. This investigation was undertaken to determine if human herpes simplex virus-8 and Epstein-Barr virus are possible etiologic viruses and to determine if they have any association with the age of the patient and/or the proliferative state of the lesion.

MATERIALS AND METHODS

Formalin fixed, routinely processed, and paraffin embedded surgical specimens of 15 angiofibromas were submitted to PCR for EBV and HHV-8, while in situ hybridization was also employed for EBV. Immunohistochemical analysis for ki-67 was performed using MIB immunostaining.

RESULTS

None of the tumors were positive for HHV-8. The PCR technique produced a false positive reaction in five cases, with all cases non-reactive with EBV-ISH. The age of the patients did not show correlation with the Ki-67 labeling index.

CONCLUSION

Angiofibroma does not appear to be associated with either HHV-8 or EBV, thereby excluding these viruses as potential etiologic agents. The lack of a correlation between the proliferative index and the age of the patient suggests the proposed puberty induced, testosterone-dependent tumor growth may not play a significant role in tumor development.

Juvenile nasopharyngeal angiofibroma: an immunohistochemical characterisation of the stromal cell

AIMS

Juvenile nasopharyngeal angiofibroma (JNA) is a rare tumour occurring almost exclusively in young adult males. Although histologically benign, it can be locally aggressive with a significant recurrence rate. The finding of activating beta-catenin gene mutations in the stromal cells indicates these are the neoplastic cells and supports the association of JNA and familial adenomatous polyposis (FAP). Previous immunohistochemical studies have demonstrated a null or focal myoepithelial immunophenotype in the stromal cells. Recently, expression of several growth factors and oncoproteins including CD117 (c-kit) in the stromal cells has been demonstrated. Our objective is to evaluate the immunohistochemical phenotype of the stromal cell of JNA, particularly within the proliferative zone of the tumour, by application of antibodies against MNF116, CAM5.2, S-100, CD31, CD34, CD99, CD68, vimentin, EMA, SMA, desmin, calponin, Bcl-2 and (CD117) c-kit in a series of 54 cases.

METHODS

A routine immunohistochemical protocol was applied to representative paraffin sections of 54 JNAs collected from the Port Moresby General Hospital, Papua New Guinea, and Princess Alexandra and Royal Brisbane Hospitals, Queensland, Australia. Immunoexpression of each antigen was assessed in the stromal cells and the vessels.

RESULTS

The majority of stromal cells in more than half of the cases demonstrated no staining with any of the 14 antibodies other than vimentin. Of 54 cases, 22 contained a microvascular component (usually peripherally located and indicating the active growth front of the tumour) in which the stromal cells demonstrated a hybrid immunophenotype with both smooth muscle and endothelial differentiation. c-kit was negative in all cases.

CONCLUSIONS

The majority of stromal cells have an undifferentiated immunophenotype with no evidence of epithelial, myoid, endothelial or other lineage specific differentiation. In the microvascular component the stromal cells appear able to show smooth muscle or endothelial differentiation. No c-kit expression was identified.

Genetic alterations in juvenile nasopharyngeal angiofibromas

Juvenile nasopharyngeal angiofibroma (JNA) is a rare benign neoplasm of the nasopharynx that accounts for 0.5% of all head and neck tumors. Although histologically benign in appearance, JNAs are locally aggressive and destructive, spreading from the nasal cavity to the nasopharynx, paranasal sinuses, and orbit skull base with intracranial extension. The gender selectivity of JNA and the relatively young age at diagnosis suggest hormone-dependent development. Hormonal disorders have been reported in patients with JNA, and androgen and estrogen receptors have been identified in tumor tissue; however, a hormonal influence on JNA is controversial. Recent studies have attempted to further delineate the pathogenesis of JNA through analysis of genetic and molecular changes. Understanding of the molecular mechanisms involved in JNA might improve prevention, prognosis, and treatment of this tumor. In this review, we discuss published studies addressing the possible molecular pathways that might be involved in the development of JNA.

Immunohistochemical analysis of growth mechanisms in juvenile nasopharyngeal angiofibroma

Angiogenic factors are discussed to participate in growth and promotion of juvenile nasopharyngeal angiofibroma (JNA). However, only few data are available and mechanisms remain unclear. In the presented study we analysed the expression and subcellular distribution of several angiogenic growth factors and receptors potentially involved in JNA-growth and -vascularisation. In a retrospective, descriptive, multicenter-study, we analysed 13 formalin-fixed, paraffin-embedded or cryopreserved JNA-tumors (eleven primary tumors and two recurrent ones) after immunohistochemical staining. We used monoclonal antibodies specific for transforming growth factor beta 1 (TGF-beta(1)), basic fibroblast growth factor (bFGF), the VEGF-receptors 1 and -2 (FLT-1 and FLK-1), and the hypoxia inducible factor (Hif-1alpha). Data were compared to the vessel density. Quantitative analysis of staining intensities was performed by a computer assisted quantification technique. Endothelial and stromal compartments of the samples were analysed separately. Data were compared to vessel densities and patients data. The VEGF-Receptor-2 (FLK) was frequently unregulated in the stroma and endothelium of those samples with high vessel densities. Similarly, we observed high bFGF- and TGF-beta(1) levels in the stroma of strong vascularised samples. No correlations of expression levels to patients' data were found. The reported data support the concept of JNA-growth and -vascularisation driven by factors released from stromal fibroblasts. Therefore, inhibition of these factors might be beneficial for the therapy of inoperable JNA.

Steroid hormone receptor expression in nasopharyngeal angiofibromas. Consistent expression of estrogen receptor beta

Nasopharyngeal angiofibroma is an uncommon tumor arising in adolescent males, suggesting that the tumor may be hormonally responsive. Previous studies have found androgen receptor (AR) expression but variable expression of estrogen receptor (ER). The recently described ss receptor for estrogen has not been analyzed in angiofibroma. We analyzed 13 cases of nasal angiofibroma by immunohistochemical analysis for the presence of ARs, progesterone receptors (PR), and ER-a and ER-ss. All 13 cases were positive for ER-ss, in stromal pericytic and endothelial cells, and 12 of 13 stained strongly. Five cases were positive for AR in stromal cells, most staining weakly, and with no staining in endothelial or pericytic cells. None of the cases displayed staining for ER-a or PR. The findings confirm that nasopharyngeal angiofibromas express ER and suggest that new modulators of ER-ss activity may provide an alternative therapy for these lesions.

Proliferation, angiogenesis and hormonal markers in juvenile nasopharyngeal angiofibroma

OBJECTIVES

Juvenile nasopharyngeal angiofibroma (JNA) is a highly vascular and locally invasive tumor that exclusively affects male adolescents. Sex hormones are first discussed to clarify the etiology of JNA. Recently with the advances in the field of cell biology angiogenetic markers, proliferation markers and growth factors are investigated to identify the molecular basis of JNA as all neoplasm. In this study we tried to evaluate the expression of proliferation, angiogenesis and hormonal markers in JNA.

METHODS

Immunohistochemical analysis were performed on paraffin-embedded 27 JNA samples which were obtained from the patients operated at University of Hacettepe Department of Otorhinolaryngology, a tertiary care center. Estrogen receptor (ER), progesterone receptor (PR), proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF) and transforming growth factor beta (TGF-beta) specific antibodies were used and evaluated by light microscopy

RESULTS

Two of 27 cases were ER positive. Nine of 27 cases were positive for PR. All of the cases were stained with PCNA. Twenty-four of 27 cases stained with VEGF. TGF-beta was positive in 14 of 27 cases. All recurrent cases were stained with PCNA and VEGF; just three of them were stained with TGF-beta.

CONCLUSIONS

Hormonal markers ER and PR did not seem to play a role in pathogenesis of JNA. PCNA, VEGF and TGF-beta may play a role in the pathogenesis of JNA by promoting angiogenesis and proliferation, but this role did not seem to have a relation with hormonal markers.

Expression and localization of steroid receptors in human nasal mucosa

OBJECTIVE

To investigate the expression of glucocorticoid receptor (GR), oestrogen receptor (ER), progesterone receptor (PR) and androgen receptor (AR) in nasal mucosa.

MATERIAL AND METHODS

Human turbinates were obtained after turbinectomy from seven patients. The expression and localization of steroid receptors were examined using reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry.

RESULTS

Using RT-PCR, GR and ER alpha mRNA were detected in all cases. In contrast, ER beta, PR and AR mRNA were found in five, four and six cases, respectively. Using immunohistochemistry, antibodies to GR showed the presence of GR within all cells of nasal mucosa, with the highest quantities of GR being localized in epithelial cells, submucosal glands and inflammatory leukocytes. Immunohistochemical analysis of sex steroid receptor revealed that anti-ER alpha antibody labelled mainly mast cells and anti-ER beta antibody labelled submucosal glands, and that no PR or AR expression was detected in any of the samples tested.

CONCLUSIONS

The role of ER in mast cells and submucosal glands has not been well clarified. However, precise knowledge of the identity and distribution of sex steroid receptor should be of considerable interest in understanding the role of sex hormones in upper airway diseases such as allergic and non-allergic rhinitis.

Urinary cytologic findings in patients with benign and malignant adenomatous polyps of the prostatic urethra

CONTEXT

Urethral adenomatous polyps with prostatic epithelium (also known as benign prostatic epithelial polyps [BPEPs]) are a documented cause of hematuria, dysuria, and hematospermia, conditions that may prompt cytologic evaluation of urine.

DESIGN

The urine cytologic test findings in 5 cases of biopsy-proven BPEPs and in 1 case of prostatic ductal adenocarcinoma (PDA) that presented as a urethral polyp were retrospectively evaluated. Immunocytochemical stain for prostate-specific antigen (PSA), prostatic acid phosphatase (PAP), and high-molecular-weight cytokeratin (34betaE12) were used in evaluation of the lesions.

RESULTS

In 4 of 5 cases of BPEPs, clusters of bland columnar cells with uniform, oval nuclei were seen. Positive immunostaining for PSA and PAP confirmed the prostatic origin of the clusters in 2 cases. One urine sample contained abundant goblet cells and extracellular mucin, consistent with intestinal metaplasia coexisting in the bladder biopsy specimen. The urine sample in the fifth case of BPEPs contained no columnar cells. The last case had multiple urine cytologic evaluations that demonstrated PSA-positive, malignant-appearing clusters of columnar cells. A biopsy specimen of the polyps was described as a high-grade prostatic intraepithelial neoplasm in adenomatous polyp. However, in this patient, PDA was diagnosed on transurethral resection of the prostate specimen 4 years after the initial urine cytologic test.

CONCLUSION

Benign prostatic epithelial polyps should be considered in the differential diagnosis of clusters of columnar cells in urine cytologic testing. Cells with malignant nuclear features should instigate a careful search for a (prostatic) neoplasm, which may present as urethral polyps (e.g., PDA). Stains for PSA or PAP are useful adjuncts in differential diagnosis of this condition.

Glomus coccygeum in surgical pathology specimens: small troublemaker

BACKGROUND

Rarely encountered nonpathologic structures may pose diagnostic problems and cause unnecessary special investigations. More importantly, however, they may be falsely accused as culprits in unrelated pathologic processes. Glomus coccygeum is one such structure. Glomus bodies (including coccygeal glomus) consist of modified smooth muscle cells arranged in layers around small vascular channels. When found in distal extremities, they generally do not represent a diagnostic problem; however, large glomus bodies present in a pericoccygeal location (glomus coccygeum) may cause significant problems for a surgical pathologist unfamiliar with this structure.

DESIGN

We reviewed 37 coccygeal bones removed during rectal resection for carcinoma (rectal and uterine) and for various other reasons, among which was a single case of coccygodynia. Immunohistochemical and ultrastructural examinations were performed in selected cases.

RESULTS

Sharply circumscribed glomus bodies composed of various proportions of glomus cells without atypia or pleomorphism and without expansile growth or infiltration of surrounding soft tissue or bone were identified in 50% of cases. Size varied significantly (maximum 4 mm), but paradoxically the smallest glomus body (less than 1 mm) was found in the case of coccygodynia. Glomus coccygeum posed a significant diagnostic challenge to the pathologists involved in these cases, as the retrospective review found that it was diagnosed correctly in only 3 cases.

CONCLUSIONS

Glomus coccygeum is a nonpathologic structure that exhibits significant variation in size and proportion of the constitutive elements. Immunohistochemical demonstration of smooth muscle actin and neuron-specific enolase in glomus cells may be beneficial for accurate identification of this organelle.